Changes

Kveik has adapted to being fermented at relatively warm temperatures without producing off-flavors (fusel alcohols, diacetyl, or acetaldehyde), usually in the range of 30-40°C (86-104°F), but also as high as 43°C (109°F). The beer is finished fermenting within a day or two at these warmer temperatures. Årset kveik has been fermented as low as 4°C (39°F), which produced a clean and drinkable beer with a fruity aroma. They have a high alcohol tolerance of around 13-16% ABV <ref name="garshol_preiss_mbaa">[https://www.mbaa.com/publications/tq/tqPastIssues/2018/Pages/TQ-55-4-1211-01.aspx How to Brew with Kveik. Lars Marius Garshol and Richard Preiss. MBAA Technical Quarterly, 2018 Q4.]</ref>. [http://www.omegayeast.com/ Omega Yeast Labs] describes their two isolates (Voss and HotHead) as being non-phenolic, fruity, and complimenting American citrus hops. They also note that the yeast has a very high temperature range (~68-98°F or ~20-37°C), attenuates high, tends to flocculate well, and also tends to ferment faster at the mid to high temperature ranges, while producing similar ester profiles throughout the entire temperature range. Other kveik cultures generally produce subdued aromas below 20°C (68°F); different kveik cultures react differently at different fermentation temperatures <ref name="garshol_preiss_mbaa" />. Despite the fast fermentation timeframe that traditional farmhouse brewers employ and the high flocculation that some kveik have, some kveik and some beer styles/brewing conditions may still require or benefit from a more traditional brewing schedule. For example, some kveik may need more time to clean up diacetyl or hydrogen sulfide, to flocculate or settle out completely, or to completely finish attenuation. Keep mind that the farmhouse beers, brewing techniques, and drinking culture differ quite a bit from modern beers, modern brewing techniques, and modern beer packaging/consumption. For example, shelf stability is generally not a concern for farmhouse brewers. Fermenting beer with kveik on the same fast time schedule and in the same ways as the traditional farmhouse beers and without making adjustments such as increased nutrients or increased conditioning time might result in less than stellar beer for modern styles <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2804718906222972/?comment_id=2804964392865090&reply_comment_id=2805567092804820&comment_tracking=%7B%22tn%22%3A%22R%22%7D Richard Preiss, Ingo Janssen, and Dan Pixley. Milk The Funk Facebook group on not treating kveik as "super yeast". 07/24/2019.]</ref>.

Kveik mixed cultures tend to be very flocculant, even though only about 48% of the individual strains are highly flocculant (it is thought that high flocculating strains help the lower flocculating strains to flocculate). Top-harvested kveik form a thick krausen and tends to float on top of liquid even when stored in the fridge, while bottom-harvested kveik tends to form a thin layer of krausen (see the [http://www.garshol.priv.no/download/farmhouse/kveik.html Farmhouse yeast registry] to see which kveik cultures are top vs bottom harvested; the listed harvesting method should be continued so as to continue to select for the correct strains). Harvested kveik can be stored in the refrigerator as a slurry, and survive 1-2 years (a starter should be made after about 6 months of cold storage). Attenuation ranges from 60-90% for single strains, but for mixed cultures, the attenuation is usually on the higher side <ref name="garshol_preiss_mbaa" />.

Note regarding Granvin strains: Preiss is still trying to sort out which Granvin yeasts are duplicates and which are unique.

====Other Sensory Data====